The present invention relates to elastomer ball joints and is more particularly directed to ball and socket type joints as commonly used in steering linkage arms, power steering systems, front-end suspension systems and the like.
A great many different types of ball and socket joints have been utilized to interconnect various moving elements in vehicles. Typically, these ball and socket joints have used synthetic resins which are mechanically locked between the ball and the socket to provide a sliding surface construction. This sliding surface construction is quite susceptible to dirt, salt and other forms of contamination reducing the life of the joints. The contaminants can work their way between the resins and the ball and/or socket. Additionally, the mechanical lock and corresponding sliding surface construction is subject to ball pullout from the socket, especially in high angular loading applications. An additional problem is the stress buildup is not uniform.
An elastomer ball joint as described in U.S. Pat. No. 2,979,353, assigned to a predecessor corporation of the instant assignee, provides better reliability and protection against corrosive deterioration and ball pullout. U.S. Pat. No. 2,979,353 provides for an elastomeric ball joint in which elastomeric material is permanently chemically bonded to the ball member and then deformed and inserted into the open end of the socket member thereby resiliently interconnecting the socket and ball members. This ball joint configuration provides a joint adapted to accept most movements between the members by the molecular deformation of the rubber and to allow in the flexing properties of the elastomer substantial relative angular movement. However, even with this design slip may occur under high torsional windup. Also, contamination of the ball joint is possible by dirt, salt, etc. attacking the high-stress critical bond line between the elastomer and the ball. Additionally it is possible for stones and other debris to lodge in the open end of the socket that can damage the joints.
In view of the above noted problems with prior art elastomer ball joint design, it has been found desirable to develop a new and improved arrangement which would overcome such problems and be more reliable and acceptable for wide-spread use. The concepts of the subject invention are deemed to meet these needs and provide a new and improved ball joint arrangement which is simple in design, economical to manufacture, reliable, long lasting, protects against contaminants, prevents ball-stud pullout, and adapts readily to a wide variety of applications.